LG’s flagship phone is running on Nvidia’s Tegra 2 dual-core 1-GHz processor. Are two cores really better than one? After playing with the G2x, I sure think so.

Right off the bat, the power of this chip is noticeable. Switching back and forth between different menu screens is seamless, and speedier than ever. Scroll downward through the pre-loaded catalog of apps, and the icons cascade like a waterfall. When I played the Halo-esque game that comes with the phone — a taxing first-person shooter in HD — it ran with minimal choppiness while handling some fairly intense animations.

With such a powerful processor at work, it’s a bit surprising the phone only comes with 512 MB of RAM installed. That might not prove to be enough for any especially resource-hungry apps and games that will arrive in the future. But for now, the phone ran the apps I threw at it like a charm.

One downside to all that power is that the back of the handset tends to get toasty after extended periods of use. So, unless you frequently suffer from cold ears, this is probably not a desirable attribute.

The phone’s 4-inch capacitive touchscreen displays color brilliantly, though I couldn’t help but wish for a larger screen for gaming. HDMI-out is always an option, and full HD mirroring lets you use the phone as a gyroscopically sensitive controller while playing on your big screen. But an extra half-inch or so of pixel real estate would have sated my thirst just the same.

The 8-megapixel rear-facing camera takes some of the clearest, crispest photos I’ve seen on a smartphone, while the 1.3-megapixel front-facing camera worked well enough for chats. My biggest camera gripe: The delay between hitting the photo button and the “shutter” closing is far too long to accurately capture that spur-of-the-moment goofy face your friend is making.

LG went with a stock version of Android 2.2 Froyo for the G2x. Frankly, not having to deal with another manufacturer’s skin is a big plus: Interfaces like HTC’s Sense or Motoblur just feel chunky compared to the bare-bones version of the OS (and to Android purists, they’re practically a sin). Although it’s not running the latest version of Android (Gingerbread) quite yet, this phone is slated to receive the OS update sometime this summer.

T-Mobile’s network performance on the phone was adequate, but left me wanting. T-Mobile markets its HSPA+ as “4G” — a term which has grown quite murky — with “theoretical peak download speeds reaching 21 Mbps and peak upload speeds of up to 5.7 Mbps.”

But you probably won’t be seeing those speeds. Over the course of two weeks of testing in the San Francisco Bay Area, I averaged download speeds ranging between 2.5 and 5.5 Mbps, and upload speeds anywhere from 0.2 Mbps to 2.2 Mbps.

My only major quibble with the hardware design is the phone’s backbone: It’s got too damn much of it. A thin metal strip tapers up the back of the handset into the edge of the camera. In theory, the edge works perfectly as a rest for your index finger while taking a call. In practice, it just feels freaking weird.

But my minor complaints about the G2x are far outweighed by its superior under-the-hood firepower. If this is the direction that LG is taking its phones — stock operating system, beefy hardware specs, peripheral-friendly — we’re eager to see more.